Continuous method of making sheet cellulose tubes



Jan. 30, 1934. o. w. DIEFFENBACH CONTINUOUS METHOD OF MAKING SHEET CELLULDSE TUBES Filed July 29, 1933 oo/173g or' Coqqea/igg 6 767277196!" Sourc e of Elecfrzc 0&0 WJz'/fenbach Patented Jan. 30, 1934 UNITED STATES CONTINUOUS METHOD OF MAKING SHEET CELLULOSE TUBES Otto W. Dielfenbach, Baltimore, Md.

Application July 29, 1933. Serial No. 682,860

Claims.

This invention relates to tubes of the type commonly used in dispensing drinks such as soda water and the like and which tubes are usually known as straws, and tubes of larger diameter 5 for various uses in the art.

Included in the objects of the invention is the production of a non-absorbent transparent, moisture proof, non-hygroscopic and resilient tube of a cellulose or similar material preferably without the use of a separate adhesive, the tube having a smooth polished surfacenon-adhesive to dust and bacteria. The production of the tube in the preferred form embodying a strip of material spirally wound and having overlapping edge portions united by the self-adhesive properties of the material, which in the practice of the invention in the preferred form is selfadhesive when heated. The tube when completed is of integral continuous, permanent construction particularly adapted for use as a drinking straw or tube, the use of the term permanent having particular reference to the'f'treatment to which a tube so used would jected.

With the above and other objects in'view, as will be hereinafter apparent, certain preferred constructive forms ofthe invention will now be described and specifically claimed, reference being had to the accompanying drawing wherein:

Figure 1 is a side elevation of such a tube in the process of construction andj'showing the essential parts of a -machin'e used such construction.

Figure 2 is a perspective view of a completed tube. r'

Figure 3 is an -enlarged detailed view, partly in section and partly. in elevation, showing a portion of such a tube in process of construction.

Figure 4 is" a still-further. enlarged section of a portion of the tube'wall showing. the autogenous union or weld between overlapping edge portion of the strip forming the tube. .1

In the mechanism illustrated in Figure 1 it will be seen that there is provided a mandrel 10 having a diameter substantially equal to the inordinarily 'be I subterior diameter of the tube to be formed. At one side of this mandrel is a driving wheel 11 and at the other side of the mandrel is a driven wheel 12, the latter being located at a higher point than the wheel 11. These wheels are connected by a belt one portion 13 of which extends directly from the top of the wheel 11 to the bottom of the wheel 12. The belt then extends around the wheel 11 and passes at 14 to the mandrel around which it is wrapped in a spiral coil 15' having its upper end extending to the wheel 12, as at 16. From a suitable source of supply, such as a roll of the material, a strip 17 of regenerated cellulose is fed to the mandrel to pass between the portion 14 of the belt and said mandrel. Under these circumstances the motion of the belt in the direction of the arrow (A) will cause the strip 17 to wind on the mandrel in a spiral form and each convolution of the strip will overlap at its edge portion the preceding convolution of said strip, thus forming a lap joint such as is shown at 18 in Figures 3 and 4.

The material from which the strip 17 is made is regenerated cellulose or similar material. This material, when softened by the application of heat, will unite with like material so as to make a union or joint due to the self-adhesive properties of the material. Above and alined with the mandrel 10 is an electric heater 19 having a bore 20 through which thespirally wound tube passes after leaving the mandrel. The heater 19 beats the tube sufficiently to efiect autogenous union of the overlapping portions of the spiral so that, when the tube passes from the heater and cools off, these overlapping-portions are firmly bonded or welded into a unitary structure without the use of any extraneous material.

After the tubular structure passes off of the mandrel, it is conducted through a heated zone and during its passage therethrough the surface becomes sufliciently softened or semi-plastic to cause the overlapping portions to adhere as indicated in Fig. 4. The walls contract slightly under the action of the heat or due to other causes and this shrinkage assists in the adhesion of the contacting portions, so that upon cooling the walls constitute a permanently scaled tubular structure. As shown, the bore 20 of the heater is of greater'diameter than the outside diameter of the tube, which prevents contact of the tube with the surface of the heater such contact having been found to be undesirable in the apparatus in connection with which the invention has been developed to date. I have found that if the walls of the tube are cooled more rapidly by passing the tube through a cooling chamber 23, maintained at sub-atmospheric temperature, immediately upon emerging from the heated welding zone, to thereby produce a sudden chill, a more compact or denser union of the welded spiral formation results. The completed tube may be cut into desired lengths by reciprocating cutters, indicated diagrammatically at 21.

Regenerated cellulose is non-absorbent, nonhygroscopic, moisture proof self-adhesive when heated and resilient and has a smooth polished surface to which dust and bacteria do not tend to adhere. By the foregonig construction there is made an integral tubular structure and it is to be noted that the autogenous welds form a spiral reinforcement around the tube. The tube or cylinder thus becomes a spirally reinforced unjointed structure. It is therefore characterized by great strength in comparison with its lightness. Due to the intimate union of the spirally welded portions the tube possesses great resistance to deformation when subjected to pressure and immediately returns to its normal cylindrical form when the walls have been squeezed and pressed inwardly.

Cellophane sheets which are commonly used to wrap articles of commerce have their overlapping edges stuck together by the application of heated pressing irons which cause the edges to adhere sufliciently to form a closure but they can be separated or pulled apart. I have discovered, as previously stated, that by forming the tubes of regenerated cellulose, such as cellophane, having a sufiicient thickness, they can be subjected to a degree of heat which will soften the contacting surfaces of the overlapping portions so that they become tacky. In this way the overlapping portions are bound together by the self-adhesive properties of the material forming a homogenous wall of double thickness. This thickened spiral portion of the wall then becomes a reinforcing element within the wall structure. Moreover by applying the heat external to the tube, after it has passed off of the mandrel, the resulting shinkage not only promotes the union of the overlapping portions *but also serves to compact the walls and render them more dense. This action is enhanced by the sudden chilling as the tube emerges from the heating zone.

It is of particular importance that the process described is continuous, comprising the automatic winding or rolling of the straws about the mandrel, the feeding forward through the heater and cutting the straws as they emerge from the heater. Under these circumstances, the output of a single machine amounts to several thousand straws per hour. This, together with the fact that the straws can be made from the edge clippings of the sheet material makes is possible to produce the straws at a minimum of cost so that they compete at least on an even price basis with the paper straws now in use. It is also of interest that the straws made of this material are non-hydroscopic, entirey neutral and insoluble in any and all liquids used as beverages, hot or cold so that they do not aifect the taste of the drink or cause the discharge of the gas, the latter being an important effect of the paraifin coated paper straws now well known. It is also a fact that the carbonated beverages extensively dispensed are acted upon by the parafiin in such a way as to release the carbon dioxide gas in the tube, causing a deterioration of the drink and a loss of the intended flavor.

It is evident that I have produced a tubular or cylindrical structure having characteristics which are entirely distinct from tubular devices having overlapping edges that have been secured by. glue or other preliminary coating or treatment. It is inherently transparent and unlike tubes made from treated materials, such as oil, paraffin etc., the walls have a hard smooth nonadherent and glossy surface which is resistant to the collection of dust, bacteria or other foreign or deleterious particles.

For the purpose of illustrating the invention I have referred to its use for drinking straws but it is evident that tubes or cylinders made in accordance with my invention may be used for various purposes in the arts, such as containers, linings for cans and other metallic vessels etc.

I claim:

1. The continuous process of making integral, continuous sealed tubes-of circular cross section from strips of sheet cellulose material, which comprises coiling said material into tubular form about a mandrel, with helical overlapping edges, and uniting the overlapping portions by feeding the tube from the mandrel forwardly through a heated area sealing the overlapping helical edges.

2. The continuous process of making integral, sealed tubes from strips of sheet cellulose material having self-adhesive properties, which comprises coiling said material about a mandrel to form a tube with spirally overlapping edges, and feeding the tube from the mandrel into a heated zone and thus causing the engaging surfaces to adhere forming a continuous sealed tube.

3. The continuous process of making integral, seal tubes from transparent sheet cellulose material which is self-adhesive when heated, said process comprising coiling said material about a mandrel into tubular form with helically arranged 115 overlapping edges feeding the tube from the mandrel and then heating the tube until the overlapping portions are caused to adhere and the walls are compacted by shrinkage.

4. The continuous process of making integral, tubes from transparent cellulose material which is self-adhesive when heated said process comprising, forming said material about a mandrel into a tube with overlapping edges feeding the tube as formed, from the mandrel through a heated zone causing the engaging surfaces to unite to form a sealed tubular wall.

5. The continuous process of making sealed drinking tubes solely from sheet cellulose material having self adhesive properties when heated, which comprises forming the material continuously into a tube about a mandrel, feeding the tube forwardly as formed from the mandrel through a heater whereby the contacting edges of the material are sealed, the tube being main- 135 tained out of contact with the heated portions of the heater.

OTTO W. DIEFFENBACH. 

